This invention is directed to a stopper for use in the drain hole of a fixture such as a kitchen sink; and in particular to a stem guide element for engaging the stopper in a guide hole of the sink drain.
The provision of stoppers for use in conjunction with fixture drain holes has become highly specialized, and these widely used, common-place articles compete for market share in an economically significant market. Despite the proliferation of improvements in this general field, particularly as exemplified in the area of kitchen sink strainer basket type stoppers, progress continues to be made, as exemplified by the present invention.
In the case of prior art stopper stem embodiments, U.S. Pat. No. 3,525,105 Richards, issued August 1970 shows the use of a resilient spring steel stopper stem. The asembly of the stem by rivetting to its basket is most difficult and labour intensive. The stem is susceptible to damage, both by wearing of the transverse edges of the stainless steel spring, which can create hazardous cutting edges therein, and by accident such as dropping on the floor, or stepping on the stopper, which can bend or even break a leg or legs of the stem.
U.S. Pat. No. 4,232,407 Williams, issued November 1980 shows the use of a stopper stem comprising three or four depending fork tines which enter the guide hole of the fixture, to center and axially position the stopper within its fitting; also serving as a pedestal to support the stopper when it is in an upwardly withdrawn, draining condition. One disadvantage of the Williams stopper is that in moving the stopper from a draining position to a stoppering position, the stem has to be fairly precisely centered before it will enter the guidance aperture, located in the drain base spider. Thus, the centering effect of the guidance aperture is somewhat limited, and the size of guidance aperture also has to be closely controlled. Furthermore, owing to the segmented form of the stem, having three or four depending tangs, when the stem stands upon the centering spider, to support the strainer basket within the sink outlet in its function as a strainer, the basket readily becomes positioned off-center in its housing, thereby diminishing its effectiveness as a strainer.
Canadian Pat. No. 1,197,653, Mann, issued Dec. 10, 1985 shows a sink stopper having a very stiff plastic stem for use with drain guidance holes having a very restricted range of diameters.